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        <a href="netaddr-module.html">Package&nbsp;netaddr</a> ::
        Module&nbsp;util
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<h1 class="epydoc">Source Code for <a href="netaddr.util-module.html" onclick="show_private();">Module netaddr.util</a></h1>
<pre class="py-src">
<a name="L1"></a><tt class="py-lineno"> 1</tt>  <tt class="py-line"><tt class="py-comment">#!/usr/bin/env python</tt> </tt>
<a name="L2"></a><tt class="py-lineno"> 2</tt>  <tt class="py-line"><tt class="py-comment"></tt><tt class="py-comment">#-----------------------------------------------------------------------------</tt> </tt>
<a name="L3"></a><tt class="py-lineno"> 3</tt>  <tt class="py-line"><tt class="py-comment"></tt><tt class="py-comment">#   Copyright (c) 2008-2009, David P. D. Moss. All rights reserved.</tt> </tt>
<a name="L4"></a><tt class="py-lineno"> 4</tt>  <tt class="py-line"><tt class="py-comment"></tt><tt class="py-comment">#</tt> </tt>
<a name="L5"></a><tt class="py-lineno"> 5</tt>  <tt class="py-line"><tt class="py-comment"></tt><tt class="py-comment">#   Released under the BSD license. See the LICENSE file for details.</tt> </tt>
<a name="L6"></a><tt class="py-lineno"> 6</tt>  <tt class="py-line"><tt class="py-comment"></tt><tt class="py-comment">#-----------------------------------------------------------------------------</tt> </tt>
<a name="L7"></a><tt class="py-lineno"> 7</tt>  <tt class="py-line"><tt class="py-comment"></tt><tt class="py-docstring">"""utility functions"""</tt> </tt>
<a name="L8"></a><tt class="py-lineno"> 8</tt>  <tt class="py-line"> </tt>
<a name="num_bits"></a><div id="num_bits-def"><a name="L9"></a><tt class="py-lineno"> 9</tt> <a class="py-toggle" href="#" id="num_bits-toggle" onclick="return toggle('num_bits');">-</a><tt class="py-line"><tt class="py-keyword">def</tt> <a class="py-def-name" href="netaddr.util-module.html#num_bits">num_bits</a><tt class="py-op">(</tt><tt class="py-param">n</tt><tt class="py-op">)</tt><tt class="py-op">:</tt> </tt>
</div><div id="num_bits-collapsed" style="display:none;" pad="++" indent="++++"></div><div id="num_bits-expanded"><a name="L10"></a><tt class="py-lineno">10</tt>  <tt class="py-line">    <tt class="py-docstring">"""Minimum number of bits needed to represent a given unsigned integer."""</tt> </tt>
<a name="L11"></a><tt class="py-lineno">11</tt>  <tt class="py-line">    <tt class="py-name">n</tt> <tt class="py-op">=</tt> <tt class="py-name">abs</tt><tt class="py-op">(</tt><tt class="py-name">n</tt><tt class="py-op">)</tt> </tt>
<a name="L12"></a><tt class="py-lineno">12</tt>  <tt class="py-line">    <tt class="py-name">numbits</tt> <tt class="py-op">=</tt> <tt class="py-number">0</tt> </tt>
<a name="L13"></a><tt class="py-lineno">13</tt>  <tt class="py-line">    <tt class="py-keyword">while</tt> <tt class="py-name">n</tt><tt class="py-op">:</tt> </tt>
<a name="L14"></a><tt class="py-lineno">14</tt>  <tt class="py-line">         <tt class="py-name">numbits</tt> <tt class="py-op">+=</tt> <tt class="py-number">1</tt> </tt>
<a name="L15"></a><tt class="py-lineno">15</tt>  <tt class="py-line">         <tt class="py-name">n</tt> <tt class="py-op">&gt;&gt;=</tt> <tt class="py-number">1</tt> </tt>
<a name="L16"></a><tt class="py-lineno">16</tt>  <tt class="py-line">    <tt class="py-keyword">return</tt> <tt class="py-name">numbits</tt> </tt>
</div><a name="L17"></a><tt class="py-lineno">17</tt>  <tt class="py-line"> </tt>
<a name="L18"></a><tt class="py-lineno">18</tt>  <tt class="py-line"><tt class="py-comment">#-----------------------------------------------------------------------------</tt> </tt>
<a name="bytes_to_bits"></a><div id="bytes_to_bits-def"><a name="L19"></a><tt class="py-lineno">19</tt> <a class="py-toggle" href="#" id="bytes_to_bits-toggle" onclick="return toggle('bytes_to_bits');">-</a><tt class="py-line"><tt class="py-comment"></tt><tt class="py-keyword">def</tt> <a class="py-def-name" href="netaddr.util-module.html#bytes_to_bits">bytes_to_bits</a><tt class="py-op">(</tt><tt class="py-op">)</tt><tt class="py-op">:</tt> </tt>
</div><div id="bytes_to_bits-collapsed" style="display:none;" pad="++" indent="++++"></div><div id="bytes_to_bits-expanded"><a name="L20"></a><tt class="py-lineno">20</tt>  <tt class="py-line">    <tt class="py-docstring">"""</tt> </tt>
<a name="L21"></a><tt class="py-lineno">21</tt>  <tt class="py-line"><tt class="py-docstring">    Generates a 256 element list of 8-bit binary digit strings. List index is</tt> </tt>
<a name="L22"></a><tt class="py-lineno">22</tt>  <tt class="py-line"><tt class="py-docstring">    equivalent to the bit string value.</tt> </tt>
<a name="L23"></a><tt class="py-lineno">23</tt>  <tt class="py-line"><tt class="py-docstring">    """</tt> </tt>
<a name="L24"></a><tt class="py-lineno">24</tt>  <tt class="py-line">    <tt class="py-name">lookup</tt> <tt class="py-op">=</tt> <tt class="py-op">[</tt><tt class="py-op">]</tt> </tt>
<a name="L25"></a><tt class="py-lineno">25</tt>  <tt class="py-line">    <tt class="py-name">bits_per_byte</tt> <tt class="py-op">=</tt> <tt class="py-name">range</tt><tt class="py-op">(</tt><tt class="py-number">7</tt><tt class="py-op">,</tt> <tt class="py-op">-</tt><tt class="py-number">1</tt><tt class="py-op">,</tt> <tt class="py-op">-</tt><tt class="py-number">1</tt><tt class="py-op">)</tt> </tt>
<a name="L26"></a><tt class="py-lineno">26</tt>  <tt class="py-line">    <tt class="py-keyword">for</tt> <tt class="py-name">num</tt> <tt class="py-keyword">in</tt> <tt class="py-name">range</tt><tt class="py-op">(</tt><tt class="py-number">256</tt><tt class="py-op">)</tt><tt class="py-op">:</tt> </tt>
<a name="L27"></a><tt class="py-lineno">27</tt>  <tt class="py-line">        <tt id="link-0" class="py-name" targets="Method netaddr.address.Addr.bits()=netaddr.address.Addr-class.html#bits"><a title="netaddr.address.Addr.bits" class="py-name" href="#" onclick="return doclink('link-0', 'bits', 'link-0');">bits</a></tt> <tt class="py-op">=</tt> <tt class="py-number">8</tt><tt class="py-op">*</tt><tt class="py-op">[</tt><tt class="py-name">None</tt><tt class="py-op">]</tt> </tt>
<a name="L28"></a><tt class="py-lineno">28</tt>  <tt class="py-line">        <tt class="py-keyword">for</tt> <tt class="py-name">i</tt> <tt class="py-keyword">in</tt> <tt class="py-name">bits_per_byte</tt><tt class="py-op">:</tt> </tt>
<a name="L29"></a><tt class="py-lineno">29</tt>  <tt class="py-line">            <tt id="link-1" class="py-name"><a title="netaddr.address.Addr.bits" class="py-name" href="#" onclick="return doclink('link-1', 'bits', 'link-0');">bits</a></tt><tt class="py-op">[</tt><tt class="py-name">i</tt><tt class="py-op">]</tt> <tt class="py-op">=</tt> <tt class="py-string">'01'</tt><tt class="py-op">[</tt><tt class="py-name">num</tt><tt class="py-op">&amp;</tt><tt class="py-number">1</tt><tt class="py-op">]</tt> </tt>
<a name="L30"></a><tt class="py-lineno">30</tt>  <tt class="py-line">            <tt class="py-name">num</tt> <tt class="py-op">&gt;&gt;=</tt> <tt class="py-number">1</tt> </tt>
<a name="L31"></a><tt class="py-lineno">31</tt>  <tt class="py-line">        <tt class="py-name">lookup</tt><tt class="py-op">.</tt><tt class="py-name">append</tt><tt class="py-op">(</tt><tt class="py-string">''</tt><tt class="py-op">.</tt><tt class="py-name">join</tt><tt class="py-op">(</tt><tt id="link-2" class="py-name"><a title="netaddr.address.Addr.bits" class="py-name" href="#" onclick="return doclink('link-2', 'bits', 'link-0');">bits</a></tt><tt class="py-op">)</tt><tt class="py-op">)</tt> </tt>
<a name="L32"></a><tt class="py-lineno">32</tt>  <tt class="py-line">    <tt class="py-keyword">return</tt> <tt class="py-name">lookup</tt> </tt>
</div><a name="L33"></a><tt class="py-lineno">33</tt>  <tt class="py-line"> </tt>
<a name="L34"></a><tt class="py-lineno">34</tt>  <tt class="py-line"><tt id="link-3" class="py-name" targets="Variable netaddr.util.BYTES_TO_BITS=netaddr.util-module.html#BYTES_TO_BITS"><a title="netaddr.util.BYTES_TO_BITS" class="py-name" href="#" onclick="return doclink('link-3', 'BYTES_TO_BITS', 'link-3');">BYTES_TO_BITS</a></tt> <tt class="py-op">=</tt> <tt id="link-4" class="py-name" targets="Function netaddr.util.bytes_to_bits()=netaddr.util-module.html#bytes_to_bits"><a title="netaddr.util.bytes_to_bits" class="py-name" href="#" onclick="return doclink('link-4', 'bytes_to_bits', 'link-4');">bytes_to_bits</a></tt><tt class="py-op">(</tt><tt class="py-op">)</tt> </tt>
<a name="L35"></a><tt class="py-lineno">35</tt>  <tt class="py-line"> </tt><script type="text/javascript">
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